Electrical connector



Dec. 23, 1969 J. E. ARNOLD v 3,486,164

ELECTRICAL CONNECTOR Filed Feb. 1, 1967 INVENTOR JOHN A. ARA/0Z0 30 /5 ATTORNEYS United States Patent 3,486,164 ELECTRICAL CONNECTGR John E. Arnold, Garden City, Mich, assignor to Detroit Switch Cor-1)., Grosse Pointe Park, Mich., a corporation of Michigan Filed Feb. 1, 1967, Ser. No. 613,269 Int. Cl. Hillr 13/50, 7/12 US. Cl. 339150 9 Claims ABSTRACT OF THE DISCLOSURE A terminal post having first and second bores opening at one end of the post and intersecting one another within the post to respectively receive a conductor lead and a fastener therein for removably securing the lead in electrically conductive contact with the post. Two of said posts are mounted in side by side relation in a body member .of a push button switch with said one ends of the posts disposed in recesses at one end of the body to provide for removable mechanical and electrical connection of a pair of conductor leads to the switch.

An object of the present invention is to provide an improved terminal binding post which facilitates the removable connection of a conductor lead to the post in a secure manner.

Another object is to provide an improved contact member adapted for switch actuation to make and break an electrical circuit at one end and at the other end for convenient removable connection of a lead thereto.

A further object is to provide an improved switch assembly incorporating a terminal post of the above character recessed from the exterior surfaces of the switch body and confined on all but one side in an insulator body to provide electrical insulation around the area in which an uninsulated portion of a conductor is connected to the post, but which permits connection or disconnection of a conductor from the post in a quick and efficient manner.

Other objects, advantages and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a perspective view of a cylindrical push button switch assembly constructed in accordance with the present invention and incorporating a pair of the improved terminal posts of the present invention.

FIG. 2 is a top plan view of the switch assembly of FIG. 1.

FIG. 3 is a vertical sectional view taken on the line 33 of FIG. 2 through the upper half of the switch assembly, and in vertical center section through the lower half of the assembly.

FIG. 4 is an enlarged end view of the terminal post shown by itself looking at the head end of the post.

FIG. 5 is a side elevational view of the terminal post on the scale of FIG. 4.

FIGS. 6 and 7 are fragmentary plan views of the top surfaces of the head of the post viewed in the direction of arrows 6 and 7 respectively of FIG. 5.

FIG. 8 is a fragmentary perspective view of a modified form of terminal post also in accordance with the present invention.

Referring first to FIGS. 4-7 inclusive, the terminal post 10 of the present invention is adapted to serve as an electrical connector between an electrical conductor, such as single or multiple strand wire, and some other conductive member such as a switch contact or the like, as will become apparent subsequently herein. Post 10 preferably is made of electrically conductive material such as brass and has a cylindrical shank 12 reduced in diameter at its lower end to form a contact point 14 which has a layer 15 of silver suitably affixed to its end face, as by furnace brazing. The upper end of post 10 includes a larger diameter cylindrical shoulder 16 integrally joined to a head 18 of still larger diameter. When post 10 is to be used in a switch assembly 60 as described hereinafter, head 18 may be milled or ground flat on two diametrically opposite sides 20 and 22 thereof (FIG. 4), leaving diametrically opposed end surfaces 24 and 26, The upper end face of head 18 comprises a flat central surface 28 disposed perpendicular to the axis 30 of shank 12, and sloping flat surfaces 32 and 34 which extend one from each transverse edge of surface 28 at a downward incline in diverging relation to one another to a junction with surfaces 24 and 26 respectively (FIG. 5).

Post 10 is provided with two intersecting bores 36 and 38 the upper ends of which open at the end face of head 18 on opposite sides of shank axis 30. Preferably bores 36 and 38 are oriented such that their respective axes 40 and 42 intersect one another, preferably at an angle of 90 degrees or less and at a mutual intersection point with axis 30 as shown in FIG. 5. Also, surfaces 32 and 34 are respectively disposed perpendicularly to axes 40 and 42. By way of example, bores axes 40 and 42 are disposed respectively at acute angles A and B relative to shank axis 30, angles A and B preferably being equal to one another and about 35 degrees. The vertex angle of surfaces 32 and 34 plus angles A and B thus totals 180 degrees in the above example.

Bore 36 is internally threaded to receive a threaded fastening member such as a set screw 44 (FIG. 3) and terminates at its inner end at a blind end Wall 46 in shank 12. Bore 38 may likewise terminate at a blind end within shank 12, or may extend completely through post 10 so that its lower end opens at shank 12 as illustrated in FIGS. 3 and 5. Preferably the upper end of bore 38 is chamfered to provide a beveled surface 50 (FIGS. 4 and 7) and the cylindrical wall of bore 38 is smooth to facilitate axial insertion of one end of a conductor lead 52, such as the end of a multiple strand electrical cable from which the insulation has been stripped as illustrated in FIGS. 1 and 3.

To removably secure lead 52 to post 10, lead 52 is slidably inserted straight into bore 38 until its lower end registers, or preferably is below, the intersection of bore 38 with bore 36. Then set screw 44 is screwed into bore 38 with a screw driver 54 as illustrated in FIG. 1 to thereby drive the beveled end 56 of the set screw against lead 52 until the same is securedly clamped frictionally in bore 38. Although set screw 44 may be made of brass or even plastic, it is preferably made of steel or similar material which is harder than the aluminum or copper materials employed in most electrical leads. Hence set screw 44, when driven against lead 52 with ordinary hand torque pressure, will deform or squash the bare end of lead 52 as illustrated in FIG. 3 so that lead 52 is mechanically locked as well as frictionally clamped in bore 38. In addition, when angles A and B total less than degrees, the inclination of set screw 44 relative to the inserted lead causes one edge to bite into the lead and develop a force component acting to pull the lead further into bore 38. This chisel engagement also causes the set screw to more readily deform the lead, thus facilitating penetration of the same to provide a more secure mechanical lock of the lead in the bore. To disconnect the conductor, set screw 44 is merely backed off with a screw driver until the same is disengaged from lead 52, whereupon lead 52 may be easily withdrawn from bore 38.

It is to be noted that the above procedure does away with the time consuming and frustrating procedure of curling the end of the lead to wrap it around the usual upright headed screw binding post of the prior art. In addition, the operations of inserting lead 52, or removing the same, and the tightening or loosening of the set screw 44, are both performed in a zone or area facing the end of head 18 remote from shank 12, as distinguished from connectors requiring both side and end access for connection and disconnection of the conductor. This feature results from the inclination of both bore 36 and bore 38 at acute angles to axis 30 of shank so that the open ends of these bores are both disposed in the end face of head 18, and is particularly advantageous when post 1!) is combined in cooperative relationship with an electrical connector assembly in accordance with the present invention, such as with the cylindrical push button switch assembly 60 illustrated in FIGS. 1, 2 and 3.

Referring in detail to FIGS. 1, 2 and 3, switch 60 includes a cylindrical body 62 preferably made of plastic having good electrical insulating properties. Body 62 has an exposed radial end face 64 with a pair of laterally spaced recesses or pockets 66 and 68 extending axially therein and separated by a partition portion 70 to insulate the pockets from one another. Body 62 is provided with a pair of stepped bores 72 which extend one from each of the pockets to the lower end of body 62 parallel to the axis of the body for slidably receiving the shanks 12 of a pair of identical posts 10 and 10 therein as shown in FIGS. 2 and 3. The contact ends 14 project beyond the lower end of body 62 and heads 18 are disposed completely within the associated pockets 66 and 68 with their end faces 28 spaced inwardly from end face 64. Shoulder 16 of each post seats on the counterbore shoulder 74 to secure the post against axial movement in one direction, and a snap ring 76 is inserted in a circumferential groove 78 of shank 12 to secure the post in the opposite direction on body 62.

Preferably, the axial side walls of pockets 66 and 68 are spaced from the associated heads 18 so that the perimeter of the pockets at end face 64 is clear of an imaginary extension of bores 36 and 38 to facilitate access to the end faces 32 and 34 of post 10.

The remaining components of switch assembly 60 are well known in the art and comprise a cylindrical casing 80 open at one end to slidably receive body 62 axially therein subsequent to axial insertion through the same end of a button subassembly 82. A helical coil spring 84 is disposed with its ends abutting against body 62 and body 82 to yieldably bias body 82 into abutment with an inturned flange 86 of casing 80 as shown in FIG. 3 to thereby maintain switch 60 in its normally open position. Button assembly 82 has a post 90 anchored at one end therein which movably carries a circular contact wafer 92 thereon which is biased toward the peened end 94 of the post 90 by a spiral compression spring 96. Post 90 is disposed centrally between the laterally spaced ends 14 of posts 10 and 10' so that when button 82 is pushed axially toward body 62, end faces of contact ends 14 strike the silvered face 98 of wafer 92 on opposite sides of the peened head 94 of post 90 to thereby electrically connect posts 10 and 10 and thus complete an electrical connection between a pair of leads connected one to each of the posts 10 and 10' of switch assembly 60 as described previously in conjunction with lead 52.

Terminal post 10 thus cooperates with body 62 to facilitate connection of the lead or leads with a recessed mounting of head 18 relative to end face 64 of the switch 60, thereby improving upon an arrangement which provides strength and protection for partition 70 and which is desired to prevent arc-over between the exposed ends of the leads. In addition, post 10 and the identical post 10' may be arranged with bores 36 and 38 oriented in reversed relation as illustrated in FIGS. 1 and 2 so that the two leads 52 secured one in post 10 and the other in post 10' are not only spaced laterally from one another but diverge outwardly from one another as they are led away from end face 64 of the switch assembly thereby providing increased protection against short circuiting between the leads. Alternatively, posts 16 and 10' may be arranged with their bores 38 side-by-side for insertion of the two stripped ends of a two-conductor cable, thus obviating the need to bend or arrange the leads out of their normal side-by-side parallel orientation prior to inserting the same in bores 38. Post 10 greatly facilitates connection of leads 52 to switch assembly 60 since the stripped ends of the conductors need not be bent but need only be inserted straight into bores 38 and set screw 44 tightened down thereon. Moreover, these operations are performed entirely at the upper end of the assembly as viewed in the drawing and thus can be performed in applications where switch 60 is not accessible from the side, as when the same is embedded in a supporting structure or side access is not feasible for other reasons. Hence connection of leads in confined areas is greatly facilitated by the terminal post of the invention.

It is to be understood that terminal post 10 may be modified without departing from the present invention as shown for example in FIG. 8. The modified terminal post 100 of FIG. 8 is identical to post 10 except for the configuration of the end face of head 18. Instead of machining the three flat surfaces 28, 32 and 34, head 18' of post 100 is formed with a conical end surface 102 the axis of which is coincident with shank axis 30. The vertex angle surface 102 is preferably the same as the angular relationship between sloping surfaces 32 and 34. Alternatively, head 18 may be formed with other end face configurations, such as a completely flat end face perpendicular to axis 30 of shank 10, although for economy of manufacture the configuration shown in FIG. 8 is presently preferred.

From the foregoing description, it will now be apparent t at the terminal post and switch assembly of the present invention provide an electrical connector which is economical to manufacture and which makes possible considerable labor savings both in initial Wiring of the switch and in subsequent maintenance, set-up and replacement operations due to the reduced time and effort needed to connect or disconnect leads to the post and switch, and which also provides a safer and more reliable electrical connector well adapted for use in heavy duty applications as well as in miniaturized components.

I claim:

1. An electrical connector comprising a body having an end face with a first recess therein, a terminal post mounted in said body and having one end disposed in said first recess with an end surface of said one end facing generally in the same direction as said end face, said post having first and second bores therein each having one end opening at said end surface and spaced from one another along said end surface, said first bore being inclined relative to said second bore and intersecting said second bore in said post, said first bore being adapted to receive a conductor lead inserted from an access zone adjacent said end face of said body into said first bore at least to the intersection with said second bore, a fastener removably secured in said second bore adapted to engage at its inner end the conductor lead inserted in said first bore to thereby secure the same in said first bore. said body having a second recess in said end face, said first and second recesses being disposed on opposite sides of the central axis of said body and being separated by a partition formed in said body, and a second terminal post identical to said first post as defined hereinabove disposed in said body with one end thereof disposed in said second recess, said first bores of said first and second posts being arranged diagonally opposite one another relative to the axis of said body and said second bores of said first and second posts are arranged diagonally opposite one another relative to the axis of said body.

2. In a switch assembly having a cylindrical metal casing open at one end coaxially receiving a cylindrical insulator body therein, and switch actuating means disposed in said casing between said body and the end of said casing opposite said one end thereof and adapted for operation from said opposite end, said body having an end face transverse to the axis thereof disposed adjacent said one end of said casing and having at least one recess therein surrounded by said end face, the improvement comprising an electrically conductive terminal post mounted in said body and having one end disposed in said recess with an end surface of said one end facing generally in the same direction as said end face, the opposite end of said post being disposed near the end of said body opposite said end face thereof and within said casing for contact with said switch actuating means, said post having first and second bores therein each having one end opening at said end surface and spaced from one another along said end surface, said first bore being inclined relative to said second bore and intersecting said second bore in said post, said first bore being adapted to receive an electrical conductor lead inserted endwise toward said one end of said casing from an access zone adjacent said end face of said body into said first bore at least to the intersection with said second bore, and a fastener removably secured in said second bore adapted to engage at its inner end the conductor lead inserted in said first bore to thereby secure the same in said first bore, said body having a second recess in said end face, said first and second recesses comprising oblong pockets disposed with their major dimensions parallel to one another and being separated by an insulating partition formed in said body, and a second electrically conductive terminal post and a second fastener associated therewith identical to said first post and said first fastener respectively as defined hereinabove disposed in said body, said heads of said first and second posts being disposed respectively in said first and second recesses, said post heads each being oblong and arranged with their major dimensions parallel to said major dimensions of the associated recesses.

3. The switch assembly as set forth in claim 2 wherein said post end surface of each of said posts is made up of first and second sloping portions disposed generally perpendicular to the axes of said first and second bores respectively in the associated post, said first and second bores of each of said posts having their open ends disposed on opposite sides of the axis of the associated post and respectively in said first and second sloping portions thereof.

4. The switch assembly as set forth in claim 2 wherein said post end surface of each of said posts is conically shaped and said first and second bores of each of said posts have said open ends thereof disposed on opposite sides of the vertex angle of said conically shaped end surface of the associated post.

5. The switch assembly as set forth in claim 2 wherein said post heads are disposed inwardly of the plane of said end face of said body and wherein the plane defined by the axes of said bores of each head is parallel to said major dimensions of said recesses and said heads.

6. The switch assembly as set forth in claim 5 wherein the perimeter of each of said recesses at said end face of said body is spaced radially from the axis of the associated one of said posts by a distance such that the perimeter falls outside an imaginary extension of said bores in the associated post.

7. The switch assembly as set forth in claim 2 wherein each of said posts has a cylindrical shank and said one end of each of said posts comprises a head portion projecting radially beyond opposite sides of the circumferential surface of said shank, said open ends of said first and second bores of each of said posts being disposed on opposite sides of the axis of said shank of the associated post.

8. The switch assembly as set forth in claim 7 wherein said first bore of each of said posts is threaded and said first and second fasteners each comprise a screw fastener inserted in the associated second bore and having an inner end adapted to engage a conductor wire disposed in said first bore of the associated post and wherein in each of said posts said first and second bores have their axes intersecting at an angle of less than degrees so that the axis of said screw fastener associated therewith is inclined relative to the conductor lead disposed in the asso ciated first bore as said associated screw fastener is tightened down toward the conductor to thereby mechanically and frictionally lock the conductor in said associated first bore.

9. In a switch assembly having a cylindrical metal casing open at one end coaxially receiving a cylindrical insulator body therein, and switch actuating means disposed in said casing between said body and the end of said casing opposite said one end thereof and adapted for operation from said opposite end, said body having an end face transverse to the axis thereof disposed adjacent said one end of said casing and having at least one recess therein surrounded by said end face, the improvement comprising an electrically conductive terminal post mounted in said body and having one end disposed in said recess with an end surface of said one end facing generally in the same direction as said end face, the opposite end of said post protruding from the end of said body opposite said end face thereof and within said casing for contact with said switch actuating means, said post having first and second bores therein each having one end opening at said end surface and spaced from one another along said end surface, said first bore being inclined relative to said second bore and intersecting said second bore in said post, said first bore being adapted to receive an electrical conductor lead inserted endwise toward said one end of said casing from an access zone adjacent said end face of said body into said first bore, at least to the intersection with said second bore, and a fastener removably secured in said second bore adapted to engage at its inner end the conductor lead inserted in said first bore to thereby secure the same in said first bore, said body having a second recess therein, said first and second recesses being disposed on opposite sides of the central axis of said body and being separated by a partition formed in said body and defining a portion of said end face, and a second terminal post and second fastener associated therewith identical to said first terminal post and said first fastener respectively as defined hereinabove disposed in said body with one end of said second post disposed in said second recess, said first bores of said first and second posts being arranged diagonally opposite one another relative to the axis of said body, and said second bores of said first and second posts being arranged diagonally opposite one another relative to the axis of said body..

References Cited UNITED STATES PATENTS 2,605,374 7/1952 Batcheller 200159 FOREIGN PATENTS 224,915 6/1957 Australia. 455,722 1/1928 Germany. 1,229,880 3/1960 France.

PETER M. CAUN, Primary Examiner US. Cl. X.R. 339272 

